Pneumatically actuated fire alarm



April 1 w. J. GARVE-Y 3,244,137

PNEUMATICALLY ACTUATED FIRE ALARM Filed Sept. 16, 1964 INVENTOR. WILL/AMJ. GARl EY United States Patent 3,244,137 INEUMATICALLY ACTUATED FIREALARM William J. Garvey, 1'77 Kimberly Road, Harrington, Ill. FiledSept. 16, 1964, Scr. No. 396,884 6 Claims. (Cl. 116-106) This inventionrelates to fire alarm devices and is concerned primarily with anapparatus which emits an audible warning signal when the ambienttemperature reaches a predetermined level.

Broadly described, the subject invention is a fire alarm device whichcomprises a pressurized medium, a thermally responsive valve adapted torelease the pressurized medium when the ambient temperature reaches apredetermined level, and a pressure-sensitive sound-emitting deviceadapted to emit a sound whenever the medium is released, whereby awarning signal is produced when the ambient temperature reaches suchpredetermined level.

Automatic fire alarm devices are known in the art. It is conventional insuch devices to employ a container of compressed propellant with afusible plug which is disposed in an outlet tube so as to function as athermally responsive valve. When the ambient temperature reaches apredetermined level, the plug melts and the propellant is released andthereafter passed through a sound-emitting device. However, as thepropellant escapes, the molten plug is cooled and solidified by theescaping, expanding vapors, thereby wholly or partially blocking theoutlet tube. It is, therefore, necessary that the ambient temperatureactually reach a temperature in excess of the predetermined meltingtemperature for the propellant to be effectively released. Furthermore,the fact that the fusible plug must be positioned internally in theoutlet tube precludes its direct exposure to the surroundings. Thus,there is always a delay in emission of the warning signal correspondingto the time necessary for heat from the surroundings to be conducted tothe fusible plug.

Accordingly, it is an object of the present invention to provide a newand improved fire alarm device employing a valved container which storespressurized propellant, a sound-emitting member adapted to emit a shrillalarm upon release of the pressurized propellant, and a thermallyresponsive member adapted to cause the opening of the valve controllingthe emission of the pressurized propellant when the ambient temperaturereaches a predetermined level.

It is another object of the present invention to provide a fire alarmdevice of the character described wherein the thermally responsivemember is disposed externally of the valved container of pressurizedpropellant.

It is yet another object of the present invention to provide a firealarm device of the character described wherein an empty container ofpressurized propellant may be replaced with a fresh container wherebythe sound-emitting member may be re-utilized.

A further object of the present invention is to provide a fire alarmdevice of the character described wherein the sound-emitting member isutilized to open the valve, thereby resulting in an alarm. devicecomprising a minimum number of parts.

A still further object of the present invention is to provide a firealarm device of the character described wherein the thermally responsivemember is replaceable for resetting and adjustment of the device.

Still another object of the present invention is to provide a fire alarmdevice of the character described, which is easily fabricated frominexpensive and readily available parts, which is quickly installable,and which is reliable in operation.

These and other objects, advantages, and features of 3,244,137 PatentedApr. 5, 1 966 the present invention will be apparent from the followingdescription, and by way of illustration, but not of limitation, anexemplary embodiment of the present invention is shown in theaccompanying drawing, in which:

FIGURE 1 is a fragmentary side elevation of an em.- bodiment of thepresent invention;

FIGURE 2 is a top plan view thereof;

FIGURE 3 is an enlarged sectional view taken along line 3-3 in FIGURE 1;

FIGURE 4 is a sectional view taken along line 44 in FIGURE 2;

FIGURE 5 is a view corresponding toFIGURE 1, but showing the deviceemitting its warning signal; and

FIGURE 6 is a fragmentary side elevation of the thermally responsiveportion of another embodiment of the present invention.

With reference to the drawing, FIGURES 1 and 2 illustrate a fire alarmdevice 11 produced in accordance with the present invention. Aconventional aerosol container 12, suitable for storing a non-flammablepropellant under pressure (hereinafter described), is provided with anoutlet valve 13 (see FIGURE 4) adapted to release the propellant whenmechanically actuated. While many types of outlet valves may beemployed, it is preferred to use the mechanism shown in the drawing (seeFIG- URE 4). Valve 13 comprises an outlet tube 14 closed at the bottomby a disk 15, which is preferably formed integrally with tube 14. Aplurality of openings 16 is provided in the lower portion of tube 14,adjacent disk 15. Each of the openings 16 passes through the wall oftube 14 and communicates with a hollow central portion thereof. Aflexible valve seal 17, formed of rubber, neoprene or other similarmaterial, holds outlet tube 14 in position in a top 19 of aerosolcontainer 12. Valve seal 17 normally fits flush against disk 15 (asshown in FIGURE 4), thereby covering all of the openings 16, andeffectively preventing the escape of pressurized propellant from thecontainer. the openings 16 by the greater pressure inside the container12 relative to the external atmospheric pressure.

When the upper portion of outlet tube 14 is laterally displaced (seeFIGURE 5), the lower portion of the tube 14 and disk 15 are displaced inan opposite lateral direction as the tube pivots in top 19. The lateralmovement of the lower portion of tube 14 pulls one side of disk 15 awayfrom valve seal 17, uncovering at least one of the openings 16 in tube14. The pressurized propellant then escapes from the aerosol container12, passing through the exposed opening 16 and out the outlet tube 14.Return of outlet tube 14 to its normal vertical disposition (as inFIGURE 4) stops the release of the propellant, valve seal 17 againfitting flush against disk 15 and thereby covering and blocking all ofthe openings 16.

A whistle 20 is mounted directly on outlet tube 14 so that propellantescaping through outlet tube 14 passes through whistle 20, therebycausing the emission of an audible warning signal. Whistle 20 (seeFIGURE 4) comprises a whistle tube 21 having a generally semicircularopening 18 cut therein. A solid plug 22 seals the upper portion of tube21 and thus prevents escape of propellant from the upper end of tube 21.A whistle insert member 25 is adapted to fit flush within the lowerportion of tube 21. The flat upper surface 27 of member 25 is inclined(see FIGURE 4) and together with tube 21 and plug 22 forms a whistlesounding chamber 28. One side of member 25 is cut away to form agenerally flat surface 26 past which escaping propellant may pass. Theflat surface 26 is cut away in the form of a groove 29 (see FIGURES 3and 4) so as to permit outlet tube 14 to be force-fitted between whistletube 21 and member 25.

Seal 17 is held tightly over With outlet tube 14 firmly inserted inwhistle 20 (as above described), valve 13 may be actuated by lateralmovement of whistle 20 (see FIGURE As will hereinafter be apparent,whistle (in addition to functioning as a sound-emitter element of thealarm device) is also a mechanical link utilized in opening outlet valve13. Thus, it is possible through the utilization of the presentinvention to provide an alarm device comprising a minimum number ofparts.

It should be understood that the present invention is not to berestricted to a whistle of any particular design and that substantiallyany whistle or other sound-emitting device can be employed so long asthe whistle or other device can be mounted directly on outlet tube 14and is adapted to be actuated by passage therethrough of escapingpropellant.

A thermally responsive arrangement is utilized to actuate outlet valve13 (via whistle 20). Thus, a brace member 30, having a generally flatbase portion and a pair of upwardly projecting end members 32, 33, isprovided in the alarm device. Base portion 30 has a recess 31 cut in itscentral portion to permit relatively free movement of outlet tube 14within the confines of recess 31. Base portion 30' rests flush againstthe top rim 34 of aerosol container 12 and is preferably fixed to rim 34by conventional means, such as retaining clips 30" (see FIGURE 4) whichare force-fitted inside rim 34, so as to prevent lateral movement ofbrace member 30 with respect to aerosol container 12. End member 32 hasa hole 35 provided therein, and a spring 36 is hooked through hole 35and is also hooked about a tab 23 which projects upwardly from whistletube 21. Spring 35 is biased to urge whistle 20 to the left (as seen inFIGURES l and 4) toward its sound-emitting disposition.

End member 33 has a projecting tab 37 extending from its upper edge. Aconnecting member 39 has holes 40, 40 formed in opposite ends thereofand also has a pair of opposite centrally disposed recesses 42, 42(defining a narrow central portion 43 formed therebetween). Member 39connects end member 33 and whistle 20, a tab 24 of whistle 20 and a tab3'7 of end member 33 passing respectively through holes 40 and 40. Thelength of connecting member 39 is such that whistle 20 is retained (inopposition to the bias of spring 36) in a generally upright non-soundemitting disposition, whereby outlet tube 14 is maintained verticallyand valve 13 is closed.

Connecting member 39 is formed of a fusible material which melts at apredetermined temperature. When the ambient temperature reaches the saidpredetermined temperature, connecting member 39 melts and pulls apart atits central portion 43, and thus whistle 2% is pulled to the left byspring 36 (as shown in FIGURE 5 Preferably, the connecting member 39 isformed of a metal alloy having a relatively low melting point. While theprecise alloy to be employed depends on the exact use for which thealarm device 11 is to be put (i.e., upon the temperature at which it isdesired that a warning signal be sounded), a preferred metal alloy isWoods metal, which comprises bismuth, 25% lead, 12.5% tin and 12.5%cadmium. Woods metal has a melting range of 158-165 F., a Brinnel No. of9.2, has 6000 psi. tensile strength, and undergoes 2-inch elongation at200 pounds slow pull.

The non-flammable propellant utilized in the alarm device 11 should bestable, nontoxic, and non-corrosive and should be of a type that willproduce a substantial pressure inside the aerosol container 12 at thetemperature at which it is desired that the alarm device 11 emit itswarning signal. A preferred propellant is dichlorodifiuoromethane, whichis commonly known as Freon-12. However, as will be apparent to oneskilled in the art, many other propellants having the proper physicaland chemical characteristics are available and can successfully beemployed.

The operation of the alarm device 11 may be summarized as follows.Normally, the device 11 is disposed in the position shown in FIGURE 1.When the ambient temperature reaches the predetermined melting range ofthe fusible connecting member 39, the member 39 separates (as at centralportion 43) into a left portion 39 and a right portion 39" (see FIGURE5). Spring 36 pulls whistle 20 to the left, and outlet tube 14 isthereby moved to the left. Movement of outlet tube 14 to the leftseparates disk 15 from valve seal 17, thereby uncovering at least one ofthe openings 16. The pressurized propellant then escapes through theexposed opening 16, outlet tube 14 and whistle 20, and a shrill warningsound is then emitted, so as to signal that the ambient temperature hasreached the predetermined level.

Performance of the alarm device is improved if a capillary tube 44 isinserted in outlet tube 14 (see FIGURE 4), The smaller diameter of thecapillary tube results in a smaller quantity of the propellant escapingduring a given length of time, thus adding to the length of time duringwhich the warning signal is emitted.

t will be apparent to one skilled in the art that other thermallyresponsive means may be utilized to actuate the valve 13 of the aerosolcontainer 12. Thus, the connecting member 39 may be provided in the formof two partially overlapping parts 45, 46 interconnected by a fusiblestrip 47 of metal alloy, such as \Voods metal (see FIGURE 6). Or, abimetallic strip (not shown) adapted to flex at a predeterminedtemperature may be connected to whistle 20, whereby flexing of the stripcauses lateral movement of whistle 2%) in order to open valve 13 (ashereinbefore described). Similarly, whistle 20 may be biased by acompressed spring (not shown) adapted to shift whistle 20 laterally uponmelting of a fusible retaining member. 7

One of the many advantages of the subject invention is theinterchangeability of its parts. It will be apparent to one skilled inthe art that the aerosol container 12 can easily be separated from bracemember 30 and whistle 20, after its propellant supply is exhausted, anda fresh aerosol container can be mounted in its place. Furthermore, inthe illustrated embodiment, it is quite simple to replace a separatedconnecting member 39, simply by maintaining Whistle 20 in a generallyupright disposition and slipping the holes 4-0, 40' in the replacementconnecting member 39 over tab 23 on whistle tube 2?. and over tab 24 onend member 33. Not only does this arrangement permit rapid resetting ofthe alarm device, it also permits easy adjustment of the predeterminedtemperature at which the alarm device emits its signal. By merelyselecting and installing a connecting member 39 having the desiredmelting temperature, the alarm device 11 can be adjusted to signalvarious predetermined temperature levels.

Another advantage of the present invention is that it can be manuallytested. This is accomplished merely by removing connecting member 39from the device, since upon removal thereof spring 36 opens valve 13 anda warning signal is emitted. Thus, it is possible to quickly, yetreliably, check the operability of the device. In this respect, thesubject invention is a marked improvement over conventional deviceswhich cannot be manually tested because they are dependent on internalfusible plugs for their actuation.

Many modifications and variations of the particular arrangementdescribed herein will be apparent to one skilled in the art, and itshould be understood that the invention is not limited in itsapplication to the details of construction and arrangement of partsspecifically described or illustrated herein. It should further beunderstood that various changes, modifications, and alterations may beeffected in the parts and elements of the described embodiment, Withoutdeparting from the spirit and scope of the present invention, asdescribed in the appended claims.

What is claimed is:

1. A fire alarm device comprising:

container means for holding a pressurized propellant;

valve means for releasing the pressurized propellant from the containermeans;

signal means adapted to emit a warning signal upon release of thepressurized propellant by the valve means, the signal means beingoperatively connected to the valve means such that movement of thesignal means opens the valve means, thereby releasing the pressurizedpropellant; and

thermally responsive valve control means adapted to efiect the movementof the signal means and thereby to open the valve means whenever theambient temperature reaches a predetermined level,

whereby the alarm device emits a warning sound whenever the ambienttemperature reaches the said predetermined level.

2. A fire alarm device comprising:

container means for holding a pressurized propellant;

valve means for releasing the pressurized propellant from the containermeans;

signal means adapted to emit a warning signal upon release of thepressurized propellant, the signal means being operatively connected tothe valve means such that movement of the signal means opens the valvemeans, thereby releasing the pressurized propellant;

biasing means urging the signal means to its valve opening position; and

thermally responsive retaining means adapted to prevent movement of thesignal means to its valve opening position so long as the ambienttemperature is less than a predetermined temperature, the retainingmeans being adapted to permit movement of the signal means to its valveopening position whenever the ambient temperature reaches the saidpredetermined level,

whereby the alarm device emits a warning sound whenever the ambienttemperature reaches the said predetermined level.

3. A fire alarm device comprising:

an aerosol container adapted to hold a volatile propellant underpressure;

valve means on the aerosol container movable between a closed positionwherein propellant is held within the aerosol container and an openposition wherein propellant is released therefrom;

Whistle means operatively connected to the valve means and providing apassage for released propellant therethrough, the whistle means beingmovable with the valve means between the closed and open positionsthereof, such that movement of the whistle means opens and closes thevalve means;

biasing means normally urging the Whistle means toward a positionwherein the valve means is opened; 55

and

thermally responsive retaining means adapted to hold the whistle meansin the position wherein the valve means is closed, the retaining meansbeing adapted to release the whistle means when the ambient temperaturereaches a predetermined level,

whereby a warning signal is emitted when the ambient temperature risesto the said predetermined level.

4. A fire alarm device as claimed in claim 3, wherein the biasing meanscomprises a spring mounted between the container and the whistle means.

5. A fire alarm device as claimed in claim 3, wherein the thermallyresponsive retaining means comprises a fusible metal member mountedbetween the container and the whistle means.

6. A fire alarm device comprising:

an aerosol container adapted to hold a volatile propellant underpressure;

valve means on the aerosol container movable between a closed positionwherein propellant is held within the aerosol container and on openposition wherein propellant is released therefrom;

whistle means operatively connected to the valve means and providing apassage for released propellant therethrough, the whistle means beingmovable with the valve means between the closed and open positionsthereof, such that movement of the whistle means opens and closes thevalve means;

a spring member mounted between the container and the whistle means, thespring member being biased to urge the whistle means toward a positionwherein the valve means is opened; and

a fusible metal retaining member mounted in opposition to the bias ofthe spring member between the container and the whistle means, theretaining memher being adapted to hold the whistle means in the positionwherein the valve means is closed, and the retaining member beingadapted to release the whistle means when the ambient temperaturereaches a predetermined level,

whereby a warning signal is emitted whenever the ambient temperaturerises to the said predetermined level.

References Cited by the Examiner UNITED STATES PATENTS 1,779,463 10/1930Connor l16114.5 2,058,288 10/ 1936 Bamonte 116l14.5 2,729,187 1/1956Bloom 116-l06 2,739,841 3/1956 Sofler 2395'77 2,760,461 8/1956 Showstock116--106 3,037,778 6/1962 Chedister et al 239577 FOREIGN PATENTS 540,3112/1956 Belgium.

LOUIS J. CAPOZI, Primary Examiner.

1. A FIRE ALARM DEVICE COMPRISING: CONTAINER MEANS FOR HOLDING APRESSURIZED PROPELLANT; VALVE MEANS FOR RELEASING THE PRESSURIZEDPROPELLANT FROM THE CONTAINER MEANS; SIGNAL MEANS ADAPTED TO EMIT AWARNING SIGNAL UPON RELEASE OF THE PRESSURIZED PROPELLANT BY THE VALVEMEANS, THE SIGNAL MEANS BEING OPERATIVELY CONNECTED TO THE VALVE MEANSSUCH THAT MOVEMENT OF THE SIGNAL MEANS OPENS THE VALVE MEANS, THEREBYRELEASING THE PRESSURIZED PROPELLANT; AND THERMALLY RESPONSIVE VALVECONTROL MEANS ADAPTED TO EFFECT THE MOVEMENT OF THE SIGNAL MEANS ANDTHEREBY TO OPEN THE VALVE MEANS WHENEVER THE AMBIENT TEMPERATURE REACHESA PREDETERMINED LEVEL, WHEREBY THE ALARM DEVICE EMITS A WARNING SOUNDWHENEVER THE AMBIENT TEMPERATURE REACHES THE SAID PREDETERMINED LEVEL.